How to use Tibetan fonts and keyboard map in Yudit
Original: Gregory Mokhin 2002-10-10
Last modified: 2003-02-05
Before you proceed: Tibetan support in Yudit is at early stages now
and is helpful for testing purposes mainly. You can type Tibetan
using Wylie transliteration and you will have proper conversion to
Unicode symbols as you type. In many cases you will have also proper
display of Tibetan glyphs. But you can also see something
unexpected, unless you have an OpenType Tibetan font installed.
Introduction
Yudit ( http://www.yudit.org ) is a free Unicode Editor, it can be
used for editing text in Tibetan script (including Tibetan proper
and Dzongkha, used mainly in Bhutan) in Unicode.
Pre-requisites
1. Download the latest version of Yudit from www.yudit.org
Follow installation instructions from http://www.yudit.org.
2. Download utibetan.ttf font from
***
and copy it into the /usr/share/yudit/fonts or ~/.yudit/fonts
UTibetan.ttf font is available under GPL. It was developed by
Gregory Mokhin , based on glyph outlines of
LTibetan.ttf font by Pierre Robillard, who is the author of LTibetan
font and made this font available under GPL (see
http://www.interlog.com/~pierrer ).
Configuration
After installing Yudit and the fonts you need to configure the
fonts. First invoke and exit Yudit. This will create a
~/.yudit/yudit.properties file.
Edit a font property in this file, to add your Tibetan font, for instance:
yudit.font.TrueType=arial.ttf,utibetan.ttf...
Select Tibetan for input in Yudit gui. This is a clustering kmap -
which means that a whole cluster needs to be entered to get proper shaping.
Tibetan text rendering.
It is important to keep in mind the difference between proper
encoding of a text (that means, correct Unicode values for typed
letters and syllables) and its rendering and display by a word
processor. Yudit is capable of using glyph substitution and
positioning required for proper display of Tibetan, but only in case
the font itself has OpenType tables (technically speaking, GSUB
and GPOS) and other OpenType features necessary for the rendering
engine to work properly. See the Appendix.
Utibetan.ttf is an incomplete version of the font. It contains
glyphs for basic Unicode points for Tibetan but it has no OpenType
features that are necessary for proper Tibetan support. These
features are under development. There exist other Tibetan fonts that
do support OpenType features, and Tibetan texts typed with Yudit
will be displayed properly when these fonts will be available for
public download by their authors.
Typing Tibetan
Use Wylie transliteration to type Tibetan, for example, try typing
ye shes mig gcig dri ma med
to see what manifests.
For learning Tibetan Wylie transliteration one might want to consult
an excellent document prepared by Prof. David Germano and THDL team
( http://www.thdl.org ) defining their extensions to classical Wylie
scheme, which is called "Extended Wylie." See
http://iris.lib.virginia.edu/tibet/tools/ewts.pdf
(but note the errata at
http://sourceforge.net/tracker/index.php?func=detail&aid=646583&group_id=61934&atid=502515).
Thanks to David Chandler for informing me about this.
Note that there is no standard method for typing Wylie yet, but the
differences concern mainly tibetanized Sanskrit stacks and mantras.
Please send your comments to Yudit developers and me.
Grisha Mokhin,
Moscow,
05 February 2002
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Appendix. Technical notes.
A number of Tibetan letters are combined from top to bottom, and the
Unicode chart for Tibetan does take into account that property of
Tibetan language. Unfortunately, the existing Unicode chart for
Tibetan is not sufficient for proper display of all Tibetan
syllables, and, similar to Indic scripts, it requires OpenType glyph
substitution and positioning tables to be implemented and applied
for font rendering.
Different variants of subjoined letters should be used for different
initial syllables. That is, "r" in "kr", "khr", "tr", "thr" should
be a different variant of subjoined "r", because its position in the
syllable depends on the initial (upper) part of the syllable. Same
about subjoined "ya", "wa", and "u". One should also take into
account mantric syllables, originally coming from Sanskrit, that are
quite common in Tibetan texts.
Actually, OpenType support for Tibetan is easier than for Indic
scripts. The main registered OpenType layout features that need
supporting for Tibetan script are:
'ccmp', 'blws', 'abvs' - all belonging to GSUB (glyph substitution)
'blwm', 'abvm', 'kern' - all GPOS (glyph positioning)